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Appendix D

Geotechnical Investigation Report (Tolunay-Wong Engineering, Inc.)

DAppendix

PRELIMINARY GEOTECHNICAL ENGINEERING STUDY

NORTH BEACH NAVIGABLE CANAL

CORPUS CHRISTI, TEXAS

Prepared for:

Lockwood, Andrews & Newnam, Inc.

2925 Briarpark Drive, Suite 400

Houston, Texas 77042

Prepared by:

Tolunay-Wong Engineers, Inc.

826 South Padre Island Drive

Corpus Christi, Texas 78416

August 19, 2020

Project No. 20.53.036 / Report No. 26074

TWE Project No. 20.53.036 i Report No. 26074

TABLE OF CONTENTS

9

8

7

6

5

4

3

2

1

9.3 Construction Monitoring

9.2 Design Review

9.1 Limitations

LIMITATIONS AND DESIGN REVIEW

8.2 Drainage

8.1 Site, Subgrade Preparation, and Fill Requirements

PRELIMINARY EARTHWORK CONSIDERATIONS

7.4 Pavement Maintenance

7.3 Pavement Section Material

7.2 Design Review

7.1 Discussion

PRELIMINARY PAVEMENT RECOMMENDATIONS

6.5 Sheet Pile Installation/Drivability

6.4 Global Stability Analyses

6.3 Sheet Pile Anchor System

6.2 Internal (Rotational) Stability Analyses

6.1 Design Soil Parameters

PRELIMINARY SHEET PILE RETENTION SYSTEM

5.7 Soil Erosion Susceptibility

5.6 Soil Shrink/Swell Potential

5.5 Groundwater Observations

5.4 Subsurface Soil Properties

5.3 Subsurface Conditions

5.2 Site Description and Surface Conditions

5.1 General

SITE AND SUBSURFACE CONDITIONS

LABORATORY SERVICES

3.5 Groundwater Measurements

3.4 Boring Logs

3.3 Soil Sampling

3.2 Drilling Methods

3.1 Soil Borings

FIELD PROGRAM

PURPOSE AND SCOPE OF SERVICES

1.2 Project Description

1.1 Introduction

INTRODUCTION AND PROJECT DESCRIPTION

9-1

9-1

9-1

9-1

8-2

8-1

8-1

7-5

9-1

9-1

9-1

6-6

6-6

6-6

6-4

6-3

6-1

6-1

5-3

5-2

5-2

5-1

5-1

5-1

5-1

5-1

4-1

3-2

3-2

3-1

3-1

3-1

3-1

2-1

1-1

1-1

1-1

TWE Project No. 20.53.036 ii Report No. 26074

TABLES AND APPENDICES

TABLES

Table 4-1 Laboratory Testing Program 4-1

Table 5-1 Relationship Between Plasticity Index and Shrink/Swell Potential 5-2

Table 6-1 Recommended Geotechnical Soil Design Parameters Soil Boring B-1 6-2

Table 6-2 Recommended Geotechnical Soil Design Parameters Soil Boring B-2 6-2

Table 6-3 Minimum Sheet Pile Wall Design Parameters Soil Boring B-1 6-3

Table 6-4 Minimum Sheet Pile Wall Design Parameters Soil Boring B-2 6-3

Table 6-5 Net Passive Resistance Soil Boring B-1 6-4

Table 6-6 Net Passive Resistance Soil Boring B-2 6-5

Table 7-1 Flexible Pavement Design Values for 30 year Design 7-2

Table 7-2 Recommended Minimum Typical Flexible Pavement 7-2

Thicknesses for 30 Year Design

Table 7-3 Rigid Pavement Design Values for 30 Year Design 7-3

Table 7-4 Recommended Minimum Typical Rigid Pavement 7-4

Thicknesses for 30 Year Design

Table 8-1 Compaction Requirements 8-1

APPENDICES

Appendix A: Option 3 Drainage Map by LAN

Appendix B: Soil Boring Location Plan TWE Drawing No. 20.53.036-1

Appendix C: Log of Project Borings and a Key to Terms and Symbols used on Boring Logs

Appendix D: Sheet Pile Wall Global Stability Results

Appendix E: Consolidated-Undrained Triaxial Shear Tests Results

TWE Project No. 20.53.036 1-1 Report No. 26074

1 INTRODUCTION AND PROJECT DESCRIPTION

1.1 Introduction

This report presents the results of our preliminary geotechnical engineering study performed for

the proposed North Beach Navigable Canal in Corpus Christi, Texas. Our preliminary

geotechnical engineering study was conducted in accordance with TWE Proposal No. P20-

C036R1, dated May 18, 2020. The study was authorized by the Subconsulting Agreement between

Lockwood, Andrews, and Newnam, Inc. (LAN) and Tolunay-Wong Engineers, Inc. (TWE) and

executed by Mr. Stephen A. Gilbreath, P.E. with LAN.

1.2 Project Description

We understand that a navigable canal/waterway is being proposed for construction within the

North Beach area of Corpus Christi, Texas for purposes of improving drainage characteristics of

the area and provide recreational opportunities. The total length of the canal/waterway will be

approximately 1.25 miles and vary in width with an average depth of 10 feet. A detailed plan view

provided by LAN is located in Appendix A.


2 PURPOSE AND SCOPE OF SERVICES

The purposes of our preliminary geotechnical engineering study were to investigate the general

soil and groundwater conditions within the project site and to provide preliminary geotechnical

design and construction recommendations for the proposed navigable canal.

Our scope of services performed for the project consisted of:

1. Drilling two (2) soil borings to depths of 50-ft within the project site to evaluate

subsurface stratigraphy and groundwater conditions;

2. Performing geotechnical laboratory tests on recovered soil samples to evaluate the

physical and engineering properties of the strata encountered;

3. Provide preliminary recommendations for drivability of sheet piling, global stability

of canal bulkhead sheet pile wall for determination of allowable safety factor, design

of anchor wall system for canal bulkhead wall, including passive resistance on the

anchor wall and location of anchor wall behind main wall;

4. Provide preliminary design profile and soil parameters for bulkhead wall analysis;

5. Provide guidance for erosion susceptibility/characteristics of soils near the mudline

of the sheet piles based on cross section provided by LAN;

6. Provide preliminary geotechnical design recommendations for flexible (asphalt) and

rigid (concrete) pavement sections including subgrade preparation and required

component thicknesses; and,

7. Provide geotechnical recommendations including subgrade preparation, excavation

considerations, fill and backfill placement, and overall quality control monitoring,

inspection and testing services.

Our scope of services did not include any environmental assessments for the presence or absence

of wetlands or of hazardous or toxic materials within or on the soil, air or water within this project

site. Any statements in this report or on the boring logs regarding odors, colors or unusual or

suspicious items or conditions are strictly for the information of the Client. A geological fault

study was also beyond the scope of our services associated with this geotechnical engineering

study.


3 FIELD PROGRAM

3.1 Soil Borings

TWE conducted an exploration of subsurface soil and groundwater conditions at the project site

on July 7, 2020 by drilling and sampling 2 soil borings to depths of 50-ft below grade. The soil

boring locations are presented on TWE Drawing No. 20.53.036-1 and 20.53.036-2 in Appendix B

of this report. Drilling and sampling of the soil borings were performed using truck-mounted

drilling equipment. Our field personnel coordinated the field activities and logged the boreholes.

The boring locations were staked at the site by TWE personnel. The latitude and longitude for

each boring location were determined by TWE using a hand operated GPS unit and are presented

on the boring logs. The borings were backfilled with soil cuttings and bentonite chips.

3.2 Drilling Methods

Field operations were performed in general accordance with the Standard Practice for Soil

Investigation and Sampling by Auger Borings [American Society for Testing and Materials

(ASTM) D 1452]. Typically, borings are dry-augered using a flight auger to advance the boreholes

until groundwater is encountered or until the boreholes become unstable and/or collapse. At that

point, soil borings are completed using wash-rotary drilling techniques. Samples were obtained at

intervals of 3-ft from existing ground surface to a depth of 10-ft and at intervals of 5-ft thereafter

until the boring completion depths of 50-ft were reached.

3.3 Soil Sampling

Fine-grained, cohesive soil samples were recovered from the soil borings by hydraulically pushing

3-in diameter, thin-walled Shelby tubes a distance of about 24-in. The field sampling procedures

were conducted in general accordance with the Standard Practice for Thin-Walled Tube Sampling

of Soils (ASTM D 1587). Our geotechnician visually classified the recovered soils and obtained

field strength measurements using a pocket penetrometer. A factor of 0.67 is typically applied to

the penetrometer measurement to estimate the undrained shear strength of the Gulf Coast cohesive

soils. The samples were extruded in the field, wrapped in foil, placed in moisture sealed containers

and protected from disturbance prior to transport to the laboratory.

Cohesionless and semi-cohesionless samples were collected with the standard penetration test

(SPT) sampler driven 18-in by blows from a 140-lb hammer falling 30-in in accordance with the

Standard Test Method for Standard Penetration Test (SPT) and Spilt-Barrel Sampling of Soils

(ASTM D 1586). The number of blows required to advance the sampler three (3) consecutive 6-in

depths are recorded for each corresponding sample on the boring logs. The N-value, in blows per

foot, is obtained from SPTs by adding the last two (2) blow count numbers. The compactness of

cohesionless and semi-cohesionless samples are inferred from the N-value. The samples obtained

from the split-barrel sampler were visually classified, placed in moisture sealed containers and

transported to our laboratory.

The recovered soil sample depths with corresponding pocket penetrometer measurements and SPT

blowcounts are presented on the boring logs in Appendix C.


3.4 Boring Logs

Our interpretations of general subsurface soil and groundwater conditions at the soil boring

locations are included on the boring logs. Our interpretations of the soil types throughout the

boring depths and the locations of strata changes were based on visual classifications during field

sampling and laboratory testing in accordance with Standard Practice for Classification of Soils

for Engineering Purposes (Unified Soil Classification System) (ASTM D 2487) and Standard

Practice for Description and Identification of Soils (Visual-Manual Procedure) (ASTM D 2488).

The boring logs include the type and interval depth for each sample along with its corresponding

pocket penetrometer measurements and SPT blow counts. The boring logs and a key to terms and

symbols used on boring logs are presented in Appendix C.

3.5 Groundwater Measurements

Groundwater level measurements were attempted in the open boreholes during dry-auger drilling.

Water level readings were attempted in the open boreholes when groundwater was first

encountered and after a ten (10) to fifteen (15) minute time period. The groundwater observations

are presented on the boring logs and are summarized in Section 5.5 of this report entitled

“Groundwater Observations.”


4 LABORATORY SERVICES

A laboratory testing program was conducted on selected samples to assist in classification and

evaluation of the physical and engineering properties of the soils encountered in the project borings.

Laboratory tests were performed in general accordance with ASTM International standards to

measure physical and engineering properties of the recovered samples. The types and brief

descriptions of the laboratory tests performed are presented in Table 4-1 below.

Table 4-1: Laboratory Testing Program

Test Description Test Method

Amount of Material in Soils Finer than No. 200 Sieve ASTM D 1140

Water (Moisture) Content of Soil ASTM D 2216

Liquid Limit, Plastic Limit and Plasticity Index of Soils ASTM D 4318

Density (Unit Weight) of Soil Specimens ASTM D 2937

Unconsolidated-Undrained Triaxial Compressive Strength (UU) ASTM D 2850

Consolidated-Undrained Triaxial Compression w/ Pore Water Pressure ASTM D 4767

Amount of Materials in Soils Finer than No. 200 (75-µm) Sieve (ASTM D 1140)

This test method determines the amount of materials in soils finer than the No. 200 (75-µm) sieve

by washing. The loss in weight resulting from the wash treatment is presented as a percentage of

the original sample and is reported as the percentage of silt and clay particles in the sample.

Water (Moisture) Content of Soil by Mass (ASTM D 2216)

This test method determines water (moisture) content by mass of soil where the reduction in mass

by drying is due to loss of water. The water (moisture) content of soil, expressed as a percentage,

is defined as the ratio of the mass of water to the mass of soil solids. Moisture content may provide

an indication of cohesive soil shear strength and compressibility when compared to Atterberg

Limits.

Liquid Limit, Plastic Limit and Plasticity Index of Soils (ASTM D 4318)

This test method determines the liquid limit, plastic limit and the plasticity index of soils. These

tests, also known as Atterberg limits, are used from soil classification purposes. They also provide

an indication of the volume change potential of a soil when considered in conjunction with the

natural moisture content. The liquid limit and plastic limit establish boundaries of consistency for

plastic soils. The plasticity index is the difference between the liquid limit and plastic limit.


Unconsolidated Undrained Triaxial Compressive Strength of Cohesive Soil (ASTM D 2850)

This test method determines the compressive strength of cohesive soil when subjected to strain-

controlled axial load as the sample is subjected to a confining stress. The confining stress generally

is that stress the sample is subjected to in the in-situ state. The test method provides an

approximate value of shear strength of cohesive materials in terms of confined unconsolidated

undrained (UU) stresses.

Consolidated-Undrained Triaxial Compression w/ Pore Water Pressure (ASTM D 4767)

This test method determines the strength and stress-strain relationships of a cylindrical specimen

of an intact saturated cohesive soil. Samples are isotropically consolidated and sheared in

compression without drainage at a constant rate of axial deformation (strain controlled).

Standard geotechnical laboratory test results and soil properties encountered in the project borings

are presented on the logs of borings in Appendix C of this report. Results of consolidated-

undrained triaxial compression tests performed on the selected cohesive soil samples obtained for

this study are included in Appendix E.

TWE Project No. 20.53.036

Report No. 26074

5-1

5 SITE AND SUBSURFACE CONDITIONS

5.1 General

Our interpretations of soil and groundwater conditions within the project site are based on

information obtained at the soil boring locations only. This information has been used as the basis

for our preliminary conclusions and recommendations included in this report. Due to the widely

spaced locations of the soil borings, subsurface conditions may vary significantly at areas not

explored by the soil borings. Significant variations at areas not explored by the soil borings will

require reassessment of our recommendations.

5.2 Site Description and Surface Conditions

The general site location for the project is shown on the attached Option 3 Drainage Map provided

by LAN as shown in Appendix A of this report. The North Beach Navigable Canal spans from its

southern end near Breakwater Ave. north to its northern end near Beach Ave. The current

configuration has the canal approximately 1.25 miles in length with various widths and an average

depth of ten feet. The site was occupied by existing city streets and commercial, residential, and

public buildings at the time of the field exploration. Areas where soil borings were conducted was

covered by natural vegetation and gravel.

5.3 Subsurface Conditions

Subsurface soil conditions encountered in the project boring B-1 consisted of stiff sandy silty clay

(CL-ML) to a depth of 2.5-ft which was underlain by loose silty sand (SM) to a depth of 6.5-ft.

Below this depth, loose to medium dense poorly graded sand with silt (SP-SM) was then

encountered to a depth of 23-ft. The sands were underlain by very soft to firm lean clay with sand

(CL) and fat clay (CH) that extended to a depth of approximately 43-ft. Very loose to loose clayey

sand (SC) were then encountered and continued to the termination depth of 50-ft.

The initial soil stratum encountered in soil boring B-2 consisted of very stiff sandy silty clay (CL-

ML) that extended to a depth of 2.5-ft below the natural ground surface. Below this stratum, loose

to very loose intermittent layers of poorly graded sand with silt (SP-SM), poorly graded sand (SP),

and clayey sand (SC) were encountered to approximately 23.5-ft. below existing grade. Very soft

cohesive soils consisting of lean clay (CL) and fat clay (CH) were then encountered to the

termination depth of B-2 at 50-ft below existing grade. The boring logs presenting detailed soil

layer classifications and tabulated field and laboratory test results are provided in Appendix C of

this report.

5.4 Subsurface Soil Properties

In-situ moisture contents of selected cohesive clay samples ranged from 6% to 87%. Results of

Atterberg Limits tests on selected clay samples indicated liquid limits (LL) ranging from 22 to 103

with plasticity indices (PI) ranging from 1 to 74. The amount of materials finer than the No. 200

sieve on the selected samples ranged from 60% to 99%. In-situ moisture contents of selected semi-

cohesionless and cohesionless sand samples ranged from 18% to 38%. The amount of materials

finer than the No. 200 sieve on the selected samples tested for grain size distribution ranged from


Report No. 26074

5-2

3% to 38%. Atterberg Limits testing indicated liquid limits of non-plastic to 30 and plasticity

indices of non-plastic to 11 for selected semi-cohesionless and cohesionless sand samples.

Undrained shear strengths derived from field pocket penetrometer readings ranged from 0.25-tsf

to 0.75-tsf. Undrained shear strengths derived from laboratory unconsolidated-undrained triaxial

shear (UU) strength testing ranged from 0.65-tsf to 0.94-tsf with corresponding total unit weights

of 62-pcf to 98-pcf. Shear strength of cohesive soils inferred from SPT blow counts generally

were similar. Drained shear strengths indicated by laboratory consolidated-undrained triaxial

shear (CU) strength testing are presented on the Triaxial Shear Test Reports in Appendix E.

Tabulated laboratory test results at the recovered sample depths are presented on the boring logs

in Appendix C.

5.5 Groundwater Observations

Groundwater observations show groundwater was encountered at both soil boring locations. At

soil boring B-1, groundwater was encountered at a depth of about 4.5-ft during dry-auger drilling

and, after a 15-minute waiting period, the groundwater level was at a depth of about 3.8-ft. At soil

boring B-2, groundwater was encountered at a depth of 4.0-ft during dry-auger drilling and, after

a 15-minute waiting period, the groundwater level was at a depth of about 4.8-ft.

Groundwater levels would be expected to fluctuate with climatic, seasonal, and tidal variations and

should be verified before construction. If accurate determination of the static groundwater level is

desired, more permanent standpipe piezometers should be used. Installation of more permanent

piezometers to evaluate the long-term groundwater condition was not included within the current

scope of services.

5.6 Soil Shrink/Swell Potential

The tendency for a soil to shrink and swell with change in moisture content is a function of clay

content and type which are generally reflected in soil consistency as defined by the Atterberg

Limits. A generalized relationship between shrink/swell potential and the soil plasticity index is

shown in Table 5-1 below.

Table 5-1: Relationship Between Plasticity Index and Shrink/Swell Potential

Plasticity Index Range Shrink/Swell Potential

0 – 15 Low

15 – 25 Medium

25 – 35 High

> 35 Very High


Report No. 26074

5-3

The amount of expansion that will actually occur with increase in moisture content is inversely

related to the overburden pressure. Therefore, the larger the overburden pressure, the smaller the

amount of expansion. Near-surface soils are thus susceptible to shrink/swell behavior because they

experience low amounts of overburden. Based on the soil boring data, the shallow clay soils at this

site have low potential for shrink/swell movements.

5.7 Soil Erosion Susceptibility

The cohesionless granular soils (sands, silty sands, clayey sands) which were encountered above

depths of 23-ft to 28-ft in the borings for this study are primarily fine-grained sands, some with

abundant fine seashell fragments. These materials will be prone to erosion by becoming part of

the water column when subjected to wave action as well as large water velocities below the water

surface due to turbulent flow (eddies, jets, etc.). As a result, our analyses of sheet pile walls were

based on compete erosion of the sands to a depth of 10-ft below the top of the walls. Protection

methods against erosion could consider installation of hardscape (cast-in-place concrete or precast

concrete reticulated block) at the intersection of the wall and sand along the inner face of the wall.


Report No. 26074

6-1

6 PRELIMINARY SHEET PILE RETENTION SYSTEM

We understand that the North Beach Navigable Canal will include construction of sheet pile

bulkhead walls (anchored or unanchored) on either side of the canal. Furthermore, it is our

understanding that steel, concrete, and vinyl sheet piles are being considered for the walls. As part

of design, we performed analyses to evaluate the internal (rotational) stability of the sheet pile

walls. Minimum allowable pile embedment depths were determined that would result in

acceptable factors of safety against internal (rotational) stability. The analyses also provided

maximum bending moments and maximum scaled deflections. Global (deep-seated) stability

analyses of the walls and their corresponding design soil profiles were performed to verify the

embedment depths for the design soil profiles would satisfy acceptable factors of safety against

failure.

Based on the cross-sections provided by LAN, presented in Appendix A, the top of sheet pile will

be approximately -1.5-ft from the top of the concrete walkway located behind the sheet wall. We

understand that the water level in front of the sheet pile wall is expected to be -3.5-ft on average

from the top of the concrete walkway/bulkhead. In the case of a catastrophic event occurring that

would cause complete erosion of the soil along the sheet pile wall, the depth of soil in front of the

sheet pile wall of -10-ft below the water surface was used for the analyses. This replicates a worst

case scenario and will determine the factors of safety of the walls against global (deep-seated)

stability and internal (rotational) stability failure.

6.1 Design Soil Parameters

Soil design parameters were developed for both soil borings due to the distance between the two

locations and variations in the properties of subsurface soil stratigraphy. Undrained design soil

parameters for short-term (end of construction) analyses were developed based on the field and

laboratory undrained shear strength measurements and based on our experience. Long-term

(drained) design soil parameters were developed based on consolidated-undrained (C-U) triaxial

shear tests performed, published correlations with soil index properties and based on our

experience. The design soil parameters are presented in Table 6-1 and Table 6-2 on the following

page.


Report No. 26074

6-2

Table 6-2 Recommended Geotechnical Soil Design Parameters Soil Boring B-2

Soil Layer

Soil Description

Depth Range

(ft)

γ (pcf)

γ' (pcf)

Undrained Parameters (Short-Term) Drained Parameters (Long-Term)

c (psf)

φ (°)

δ (°)

a (psf)

Ka Kp Ko e50 k

(pci) c'

(psf) φ' (°)

δ (°)

a (psf)

Ka Kp Ko

1 Very Stiff

Clay 0 - 2.5 120 58 2,800 0 0 650 1.00 1.00 1.00 0.007 200 0 27 14 0 0.38 2.66 0.55

2 Very Loose

Sand 2.5 - 5 105 43 0 27 14 0 0.38 2.66 0.55 - 20 0 27 14 0 0.38 2.66 0.55

3 Loose Sand 5 -

13.5 110 48 0 27 14 0 0.38 2.66 0.55 - 20 0 27 14 0 0.38 2.66 0.55

4

Very Loose

to Loose Sand

13.5 -

28.5 105 43 0 27 14 0 0.38 2.66 0.55 - 20 0 27 14 0 0.38 2.66 0.55

5 Very Soft

Clay

28.5 -

38 105 43 250 0 0 150 1.00 1.00 1.00 0.02 30 0 26 13 0 0.39 2.56 0.56

6 Very Soft

Clay 38 - 43 105 43 940 0 0 425 1.00 1.00 1.00 0.01 200 100 31 16 0 0.32 3.12 0.48

7 Very Soft

Clay 43 - 47 105 43 940 0 0 425 1.00 1.00 1.00 0.01 200 100 31 16 0 0.32 3.12 0.48

8 Firm Clay 47 - 50 115 53 940 0 0 425 1.00 1.00 1.00 0.01 200 100 31 16 0 0.32 3.12 0.48

Legend:

γ = Total Unit Weight

γ' = Submerged Unit Weight c = Cohesion

φ = Friction Angle

δ = Angle of Wall Friction (Steel Sheet Pile)

a = Adhesion

Ka = Active Earth Pressure Coefficient

Kp = Passive Earth Pressure Coefficient

Ko = At-Rest Earth Pressure Coefficient k = Soil Modulus Parameter

(Undrained Conditions Only)

e50 = Soil Strain Parameter for Clay Soils ( 50% undrained strength)

Notes:

1) Approximate depths are from existing ground surface at the

soil boring locations. 2) Plasticity index (PI) was used to provide a correlation of

effective friction angle for clay soils.

Table 6-1 Recommended Geotechnical Soil Design Parameters Soil Boring B-1

Soil Layer

Soil Description

Depth Range

(ft)

γ (pcf)

γ' (pcf)

Undrained Parameters (Short-Term) Drained Parameters (Long-Term)

c (psf)

φ (°)

δ (°)

a (psf)

Ka Kp Ko e50 k

(pci) c'

(psf) φ' (°)

δ (°)

a (psf)

Ka Kp Ko

1 Stiff Clay 0 - 2.5 120 58 1,000 0 0 450 1.00 1.00 1.00 0.007 200 0 24 12 0 0.42 2.37 0.59

2 Loose Sand 2.5 - 6.5

110 48 0 27 14 0 0.38 2.66 0.55 - 20 0 27 14 0 0.38 2.66 0.55

3 Medium

Dense Sand

6.5 -

18 115 53 0 27 14 0 0.38 2.66 0.55 - 60 0 27 14 0 0.38 2.66 0.55

4 Loose Sand 18 - 23 110 48 0 27 14 0 0.38 2.66 0.55 - 20 0 27 14 0 0.38 2.66 0.55

5 Very Soft

Clay 23 - 33 105 43 200 0 0 150 1.00 1.00 1.00 0.02 30 0 18 9 0 0.53 1.89 0.69

6 Firm Clay 33 - 38 117 55 650 0 0 350 1.00 1.00 1.00 0.02 100 0 27 14 0 0.38 2.66 0.55

7 Soft Clay 38 - 43 110 48 400 0 0 250 1.00 1.00 1.00 0.02 30 0 18 9 0 0.53 1.89 0.69

8 Loose Sand 43 - 48 110 48 0 27 14 0 0.38 2.66 0.55 - 20 0 27 14 0 0.38 2.66 0.55

9 Very Loose

Sand 48 - 50 105 43 0 27 14 0 0.38 2.66 0.55 - 20 0 27 14 0 0.38 2.66 0.55

Legend:

γ = Total Unit Weight γ' = Submerged Unit Weight

c = Cohesion

φ = Friction Angle

δ = Angle of Wall Friction (Steel Sheet Pile)

a = Adhesion

Ka = Active Earth Pressure Coefficient

Kp = Passive Earth Pressure Coefficient Ko = At-Rest Earth Pressure Coefficient

k = Soil Modulus Parameter

(Undrained Conditions Only) e50 = Soil Strain Parameter for Clay Soils

(50% undrained strength)

Notes:

1) Approximate depths are from existing ground surface at the soil boring locations.

2) Plasticity index (PI) was used to provide a correlation of

effective friction angle for clay soils.


Report No. 26074

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6.2 Internal (Rotational) Stability Analyses

The objectives of our analyses were to determine the minimum required sheet pile lengths (design

embedment), maximum bending moment in the sheet pile sections and the loading that the

anchoring system will experience per foot section of the sheet pile wall. Soil design parameters

were determined by analyzing the soil stratigraphy of borings that were conducted at boring

locations presented on TWE Drawing No. 20.53.036-1 and 20.53.036-2 in Appendix B of this

report.

We analyzed the proposed sheet pile wall sections for internal (rotational) stability using the

computer program CWALSHT developed by the U.S. Army Corps of Engineers (USACE) at the

Engineering Research & Development Center in Vicksburg, Mississippi. CWALSHT uses

classical methods of sheet pile analysis based on limit equilibrium methods in accordance with

USACE EM 1110-2-2503 (Design of Sheet Pile Wall). The results of the rotational stability

analyses for each location are located in Table 6-3 and Table 6-4 below. Factors of safety of 1.0

and 1.5 were used for active and passive pressure, respectively.

Table 6-3 : Minimum Sheet Pile Wall Design Parameters Soil Boring B-1

Minimum Design Parameter

Anchored Cantilever

Embedment Depth 12-ft 23-ft

Overall Height 22-ft 33-ft

Maximum Bending Moment 60 kip-in 325 kip-in

Maximum Scaled Deflection 3.0370 x 10^8 lb-in^3 1.9079 x 10^10 lb-in^3

Anchor Load 1,650 lb/ft ---

Table 6-4 : Minimum Sheet Pile Wall Design Parameters Soil Boring B-2

Minimum Design Parameter

Anchored Cantilever

Embedment Depth 13-ft 22-ft

Overall Height 23-ft 32-ft

Maximum Bending Moment 85 kip-in 410 kip-in

Maximum Scaled Deflection 3.3016 x 10^8 lb-in^3 1.9300 x 10^10 lb-in^3

Anchor Load 1,680 lb/ft ---

The following formulas are used to find the minimum required section modulus and top of wall

deflection for steel, vinyl, and concrete sheet pile sections:


Report No. 26074

6-4

𝑆 =𝑀𝑚

𝜎𝑎

∆𝑇𝑂𝑊 =∆𝑚𝑠

𝐸𝐼

Where;

𝑆 = 𝑀𝑖𝑛𝑖𝑚𝑢𝑚 𝑅𝑒𝑞𝑢𝑖𝑟𝑒𝑑 𝑆𝑒𝑐𝑡𝑖𝑜𝑛 𝑀𝑜𝑑𝑢𝑙𝑢𝑠 𝑓𝑜𝑟 𝑎 𝑆ℎ𝑒𝑒𝑡 𝑃𝑖𝑙𝑒 𝑆𝑒𝑐𝑡𝑖𝑜𝑛 𝑖𝑛 𝑖𝑛3

𝑀𝑚 = 𝑀𝑎𝑥𝑖𝑚𝑢𝑚 𝐵𝑒𝑛𝑑𝑖𝑛𝑔 𝑀𝑜𝑚𝑒𝑚𝑒𝑛𝑡 𝑖𝑛 𝑘𝑖𝑝 − 𝑖𝑛

𝜎𝑎 = 𝐴𝑙𝑙𝑜𝑤𝑎𝑏𝑙𝑒 𝑌𝑖𝑒𝑙𝑑 𝑆𝑡𝑟𝑒𝑠𝑠 𝑜𝑓 𝑀𝑎𝑡𝑒𝑟𝑖𝑎𝑙 𝑖𝑛 𝑘𝑖𝑝/𝑖𝑛2 *

∆𝑇𝑂𝑊= 𝑇𝑜𝑝 𝑜𝑓 𝑊𝑎𝑙𝑙 𝐷𝑒𝑓𝑙𝑒𝑐𝑡𝑖𝑜𝑛 𝑖𝑛 𝑖𝑛𝑐ℎ𝑒𝑠

∆𝑚𝑠= 𝑀𝑎𝑥𝑖𝑚𝑢𝑚 𝑆𝑐𝑎𝑙𝑒𝑑 𝐷𝑒𝑓𝑙𝑒𝑐𝑡𝑖𝑜𝑛 𝑖𝑛 𝑙𝑏 − 𝑖𝑛3

𝐸 = 𝑀𝑜𝑑𝑢𝑙𝑢𝑠 𝑜𝑓 𝐸𝑙𝑎𝑠𝑡𝑖𝑐𝑖𝑡𝑦 𝑓𝑜𝑟 𝑀𝑎𝑡𝑒𝑟𝑖𝑎𝑙 in lbs/in2

𝐼 = 𝑀𝑜𝑚𝑒𝑛𝑡 𝑜𝑓 𝐼𝑛𝑒𝑟𝑡𝑖𝑎 𝑓𝑜𝑟 𝑆ℎ𝑒𝑒𝑡 𝑃𝑖𝑙𝑒 𝑆𝑒𝑐𝑡𝑖𝑜𝑛 in in4

* It should be noted that the allowable stress for steel, concrete and vinyl require a factor of

reduction before application these reductions are as follows;

𝜎𝑎 𝑜𝑓 𝑐𝑜𝑛𝑐𝑟𝑒𝑡𝑒 = 0.6 ∗ 𝑓′𝑐 (minimum 𝑓′𝑐 of 5000 psi)

𝜎𝑎 𝑜𝑓 𝑣𝑖𝑛𝑦𝑙 𝑎𝑛𝑑 𝑠𝑡𝑒𝑒𝑙 = 0.5 ∗ 𝑓𝑦

6.3 Sheet Pile Anchor System

We performed analyses for passive resistance and active resistance to determine the net passive

resistance acting on the sheet pile wall anchoring system for both boring locations. The passive

resistance and active resistance were calculated using the long-term (drained) design soil

parameters for each soil boring location. The design soil parameters can be found in Table 6-1 and

Table 6-2 in section 6.1, “Design Soil Parameters” above. Our analysis assumed that the

connection of the anchoring system to the sheet pile wall will be located at the sheet pile cap (top

of sheet pile wall). The results of the analysis are provided in Table 6-5 and Table 6-6 below.

Table 6-5 Net Passive Resistance Soil Boring B-1

Kp = 2.66, Ka = 0.375 Groundwater level = 4 ft below existing grade

Depth Below Grade (ft)

Unit Weight of Soil (PCF)

Effective Overburden

Pressure (PSF) Factored Passive Resistance (PSF)

Active Resistance (PSF)

Net Passive Resistance

(PSF)

0 120 0 0 0 0

2.5 120 300 399 113 287

6.5 110 584 777 219 558

15 115 1031 1371 387 985

Note: Net passive resistance is based on passive resistance factored by 2 against failure.


Report No. 26074

6-5

Table 6-6 Net Passive Resistance Soil Boring B-2

Kp = 2.66, Ka = 0.375 Groundwater level = 4 ft below existing grade

Depth Below Grade (ft)

Unit Weight of Soil (PCF)

Effective Overburden

Pressure (PSF) Factored Passive Resistance (PSF)

Active Resistance (PSF)

Net Passive Resistance

(PSF)

0 120 0 0 0 0

2.5 120 300 399 113 287

5 105 500 665 188 478

10 110 738 982 277 705

15 105 969 1288 363 925

Note: Net passive resistance is based on passive resistance factored by 2 against failure.

Anchor Location

In consideration of sheet pile anchor placement relative to the sheet pile wall a distance sufficient

to utilize the full factored net passive resistance was calculated. Based on our analysis of the active

earth pressure wedge behind the sheet pile wall and the passive pressure wedge in front of the

anchor, a minimum distance of thirty (30) linear feet from the top of the sheet pile wall should be

maintained for all anchoring systems. A minimum depth of embedment of 2.5-ft should be

observed for all anchors used for this sheet pile wall; however, the embedment depth should

provide sufficient overburden pressure and net passive resistance to resist uplift pressure and the

anchor loads as presented in Table 6-3 and Table 6-4 of section 6.2 “Internal (Rotational)

Stability”. Preferably, the top of the anchoring system should be above the observed groundwater

levels to avoid excessive uplift pressure.

Anchor System Installation

Anchors meeting or exceeding the stated criteria in section 6.2, “Internal (Rotational) Stability),

and in the above section may consist of either concrete dead man, steel member, or sheet pile wall

attached to the pile with tie rods, or tiebacks with grouted anchors (soil nails), or helical piles, or

various configurations of steel or concrete piles.

Anchor forces, soil pressures and water loads are affected by the method of construction and

construction practices. The sequence of tightening tie rods should be specified to prevent

overstresses in isolated sections of the sheet pile wall. Anchors and tie rods should be placed and

tightened in a uniform manner so that no overstresses may occur. Backfilling above the anchor

elevation should be carefully controlled to prevent bending of the tie rods. The backfill material

should be controlled, and the thickness of compacted layers should be limited to ensure proper

compaction and drainage of the back fill material.


Report No. 26074

6-6

6.4 Global Stability Analyses

We performed global stability analyses of the sheet pile wall section using the computer program

Slide 7.0 (Rocscience 2018) to determine the adequacy of the sheet pile embedment obtained from

the internal (rotational) stability criteria. Slide is a 2D limit equilibrium slope stability program

for evaluating the safety factor, or probability of failure, of circular or non-circular failure surfaces

in soil or rock slopes. Slide analyzes the stability of slip surfaces using vertical slice limit

equilibrium methods.

Global stability analysis was performed using Spencer’s (1967) method for short-term conditions,

using undrained (total stress) parameters, and long-term conditions using drained (effective stress)

parameters. Spencer’s (1967) method satisfies both force and moment equilibriums. The results of

our global stability evaluations are presented in Appendix D of this report. According to the

guidance provided in U.S. Army Corps of Engineers (USACE) Engineer Manual for Slope

Stability (EM 1110-2-1902), the minimum required factor of safety considered appropriate for

short-term (undrained) and long-term (drained) stability analysis are 1.3 and 1.5, respectively.

Based on the results of our analyses, the global stability factor of safety for short-term and long-

term conditions, for the sheet pile embedment depth and design soil parameters considered, exceed

the minimum required factors of safety.

6.5 Sheet Pile Installation/Drivability

The most common methods of installing sheet pile walls include driving, jetting and trenching.

The type of sheet piling will often govern the method of installation. There are several types of

driving hammers that are available for sheet pile installation and can be broken down into two

separate categories; impact and vibratory hammers. Vibratory hammers are generally the faster

method of pile installation depending on the soil stratigraphy however if a penetration rate of 1-ft

per minute or less is experienced the vibratory hammer should be discontinued and an impact

hammer implemented. The prolonged use of a vibratory hammer in hard soil conditions can cause

damage to pile interlocks. The selection of the type or size of the hammer is based on the soil in

which the pile is driven, size of pile, and depth of penetration. When impact hammers are used the

hammer should be appropriately sized and a protective cap utilized to prevent excessive damage

to the pile. To ensure that piles are placed and driven to the correct alignment, a guide structure or

templates should be used. At least two templates should be used in driving each pile or pair of

piles.

Jetting is usually used to penetrate strata of dense cohesionless soils. Jetting should be performed

on both sides of the piling simultaneously and discontinued during the last 5-ft to 10-ft of pile

penetration. Adequate steps must be taken to ensure the control, treatment, and disposal of runoff

water. Sheet piling should not be driven more than 1/8 inch per foot out of plumb either in the

plane of the wall or perpendicular to the plane of the wall. Due to soil stratigraphy and intended

application of the sheet pile wall trenching is not a recommended method of installation for the

sheet pile sections. Since the anticipated subsurface soil conditions largely include very loose to

loose sands and very soft to soft clays, jetting should not be required for this site.


Report No. 26074

6-7

Additionally, we do not expect unusual difficult sheet pile placement for the subsurface conditions

encountered in the borings for this project. Although we expect that vibratory placement of sheet

piles can be accomplished for these subsurface conditions, we recommend a sheet pile contractor

be contacted to confirm this conclusion. If additional detailed information regarding drivability

for steel sheet piling, prestressed concrete sheet piling, or vinyl sheet piling is desired, please refer

to U.S Army Corps of Engineers, EM1110-2-2504, March 31, 1994, Design of Sheet Pile Walls

publication.


Report No. 26074

7-1

7 PRELIMINARY PAVEMENT RECOMMENDATIONS

7.1 Discussion

Preliminary pavement recommendations for improvement of existing roadways at North Beach

are provided below. Possible other improvements may include replacement of existing utilities

and addition of new traffic control lights.

7.2 Design Review

The methods used in our pavement analysis can be found in the AASHTO, Guide for Design of

Pavement Structures. Traffic conditions provided the City of Corpus Christi for local non-

residential traffic were used for design purposes using a 30-year design life. An annual traffic

growth rate of 0.2% was used in accordance with city requirements.

7.2.1 Flexible Pavement Design

The primary design requirements needed for flexible pavement design according to the Pavement

Design Guide include the following:

• Material Layer Coefficient;

• Soil Resilient Modulus, psi;

• Serviceability Indices;

• Drainage Coefficient;

• Overall Standard Deviation;

• Reliability, %; and,

• Design Traffic, 18-kip Equivalent Single Axle Load (ESAL)

• Design Average Daily Traffic (ADT)

• Design % Truck

The design values used for our analyses are presented in Table 7-1 on the following page for 30-

yr design life.


Report No. 26074

7-2

Table 7-1 Flexible Pavement Design Values for 30 year Design

Description Value

Design ADT and % Truck(1) Average Daily Traffic (ADT) n/a

% Truck n/a

Material Coefficients

Hot Mix Asphalt Concrete (HMAC), Type D 0.44

HMAC, Type B 0.40

Crushed Limestone (Type A, Grade 2 or better) [CLB] 0.14

Crushed Concrete (CC) 0.12

Lime Stabilized Subgrade (LSS) 0.08

Compacted Subgrade 0.035

Serviceability Indices Initial 4.2

Terminal 2.5

Soil Resilient Modulus 3,100-psi

Drainage Coefficient 1.0

Overall Standard Deviation 0.45

Reliability 80%

Design Traffic, 18-kip Equivalent Single Axle Load (ESAL) 1,000,000

Structural Number Required 4.52

(1) The Average Daily Traffic and the % truck were provided and determined by using the traffic data

parameters regarding local non-residential traffic provided by City of Corpus Christi.

Table 7-2 Recommended Minimum Typical Flexible Pavement Thicknesses for 30 Year Design

Pavement Option

HMAC, Type D

HMAC, Type B

CLB CC CS SN

SN A 3.0-in 3.0-in 8.0-in --- 12.0-in 4.60

B 2.5-in 3.0-in 8.0-in* --- 8.0-in 4.76

C 3.0-in 3.0-in --- 9.0-in 12.0-in 4.56

D 2.5-in 3.0-in --- 8.0-in* 8.0-in 4.57

(*) A layer of geogrid (Tensar TX-5 or equivalent) installed at the bottom of the crushed limestone or

crushed concrete base.

HMAC = Hot Mix Asphalt Concrete

CLB = Crushed Limestone Base (Type A, Grade 1-2)

CC = Crushed Concrete (Type D, Grade 1-2)

CS = Compacted Subgrade

SN = Structural Number


Report No. 26074

7-3

It should be noted that the upper 2.5-ft of soil at both boring locations exhibit low plasticity

properties similar to a lime stabilized subgrade and can be treated as such. Thus, low plasticity

subgrade materials were used for the pavement analyses. Sufficient monitoring and testing should

be done to observe that these properties are homogenous throughout the segments of roadway that

may be reconstructed.

Existing roadways consisting of one of the above sections or similar may meet the City of Corpus

Christi criteria for a local non-residential roadway with a 30-year lifespan at 80% reliability. Field

explorations such as coring can be implemented in order to determine the viability of the North

Beach roadway segments. As it stands now there is little to no drainage systems in place along

the two referenced roadways and consideration for flood mitigation and drainage should be taken.

7.2.2 Rigid Pavement Design

The primary design requirements needed for rigid pavement design according to the AASHTO

Guide include the following:

• 28-day Concrete Modulus of Rupture, psi;

• 28-day Concrete Elastic Modulus, psi;

• Effective Modulus of Subgrade Reaction, pci (k-value);

• Serviceability Indices;

• Load Transfer Coefficient;

• Drainage Coefficient;

• Overall Standard Deviation;

• Reliability, %; and,

• Design Traffic, 18-kip Equivalent Single Axle Load (ESAL)

The design values used for our analyses are presented in Table 7-3 below for 30-yr design life.

Table 7-3

Rigid Pavement Design Values for 30 Year Design

Description Value

28-day Concrete Modulus of Rupture 620-psi

28-day Concrete Elastic Modulus 3,860,000-psi

Effective Modulus of Subgrade Reaction 110-pci

Serviceability Indices Initial 4.5

Terminal 2.5

Load Transfer Coefficient Continuously Reinforced 2.6

Plain 3.2

Drainage Coefficient 1.0

Overall Standard Deviation 0.39

Reliability 80%

Design Traffic, 18-kip Equivalent Single Axle Load (ESAL) 1,000,000


Report No. 26074

7-4

Table 7-4 below provides the recommended minimum typical rigid pavement sections derived

from our analysis using the AASHTO Pavement Design Guide.

Table 7-4 Recommended Minimum Typical Rigid Pavement Thicknesses for 30 Year Design

Pavement Option PCC BB CLB CS

Continuously Reinforced 6.0-in 1.0-in 7.0-in 12.0-in

Plain 7.0-in 1.0-in 7.0-in 12.0-in.

PCC = Portland Cement Concrete

BB = Bond Breaker (HMAC, Type B or D)

CLB = Crushed Limestone Flexible Base (TxDOT, Item 247, Type A, Grade 1-2)

CS = Compacted Subgrade

7.3 Pavement Section Material

Hot Mix Asphalt Concrete (HMAC)

HMAC should conform to Item 340, “Dense-Graded Hot-Mix Asphalt” of the Texas Department

of Transportation (TxDOT) 2004 Standard Specifications for Construction and Maintenance of

Highways, Streets and Bridges. The HMAC should provide a minimum tensile strength (dry) of

85 to 200 psi when tested in accordance with TxDOT Test Method Tex-226-F, and should be

compacted at 92% to 96% of the theoretical density as determined from the asphaltic mixture

design prepared in accordance with TxDOT Test Method Tex-207-F “Determining Density of

Compacted Bituminous Mixtures”.

Portland Cement Concrete (PCC)

PCC should be provided in accordance with TxDOT Item 421 “Hydraulic Cement Concrete”,

2014. Concrete should be designed to meet a minimum average flexural strength (modulus of

rupture) of at least 620-psi at 28-days or a minimum average compressive strength of 4,500-psi at

28-days. Reinforcing steel consisting of deformed steel rebar should be used in accordance with

TxDOT Item 440 “Reinforcing Steel.”

The first few loads of concrete should be checked for slump, air and temperature on start-up

production days to check for concrete conformance and consistency. Concrete should be sampled

and strength test specimens [two (2) specimens per test] prepared on the initial day of production

and for each 400-yd2 or fraction thereof of concrete pavement thereafter. At least one (1) set of

strength test specimens should be prepared for each production day. Slump, air and temperature


Report No. 26074

7-5

tests should be performed each time strength test specimens are made. Concrete temperature

should also be monitored to ensure that concrete is consistently within the temperature

requirements.

Crushed Limestone Base (CLB)

CLB should conform to City of Corpus Christi Standard Construction Specification (COCC)

Section 025223 “Flexible Base” and should be moisture conditioned to -2% to +2% of the optimum

moistures and compacted to at least 98 percent of the maximum dry densities determined by

Modified Proctor (ASTM D 1557) and Standard Proctor (ASTM D 698) for flexible pavement

sections and rigid pavement sections, respectively.

Crushed Concrete (CC)

CC should conform to TxDOT Item 247, Type D, Grade 1-2 and should be compacted in the same

manner to CLB and can be substituted at the same thickness as CLB.

Compacted Subgrade (CS)

After completion of necessary stripping and clearing, the exposed soil subgrade should be carefully

evaluated by probing and testing. Any unsuitable material (shell, gravel, and organic material,

wet, soft or loose soil) still in place should be removed. The exposed soil subgrade should be

further evaluated by proofrolling with a heavy pneumatic tired roller, loaded dump truck or similar

equipment weighing at least 20-tons to ensure that soft or loose material does not exist beneath the

exposed soils. Proofrolling procedures should be observed routinely by a qualified representative

of TWE. Any undesirable material revealed should be removed and replaced in a controlled

manner with soils similar in classification or select fill.

Once final subgrade elevation is achieved and prior to placement of crushed limestone base, or

crushed concrete material, the exposed surface of the pavement subgrade soil should be scarified

to a depth of 12-in. and compacted in two, 6-in lifts, each to a minimum 95% of the maximum dry

density as determined by Standard Proctor (ASTM D 698) at a moisture content within the range

of 3% above optimum. Crushed limestone base, or crushed concrete material should be promptly

placed on the compacted, tested, and accepted subgrade.

7.4 Pavement Maintenance

Periodic maintenance of the roadway should be performed over the life of the pavement structure.

Maintaining the roadway to prevent infiltration of water into the crushed limestone base material

and subgrade soils is essential. Allowing water to infiltrate these materials will result in high

maintenance costs and premature failures.


Report No. 26074

8-1

8 PRELIMINARY EARTHWORK CONSIDERATIONS

8.1 Site, Subgrade Preparation, and Fill Requirements

Soils for backfilling behind the sheet pile walls and site filling above or below critical structures

(sheet pile anchors or streets) should be placed in controlled and compacted lifts per the

recommendations below in Section 8.2 of this report.

Areas designated to receive fill at the site should be stripped of all surface vegetation, loose topsoil

and major root systems. Any subgrade to receive fill soils, pavements, or flatwork should be proof

rolled with at least a 20-ton pneumatic roller, loaded dump truck, or equivalent, to detect weak

areas. Such weak areas should be removed and replaced with soils exhibiting similar

classification, moisture content, and density as the adjacent in-place soils.

The exposed subgrades to receive fill as well as subsequent fill materials should be compacted as

indicated below in Table 8.1.

Table 8-1: Compaction Requirements

Subgrade/Fill Type Required Compaction Level Required Moisture Level

Subgrades for General Fill 92%-95% of ASTM D 698 -2% to +3% of optimum

Subgrades for Wall Backfill 90%-92% of ASTM D 698 -2% to +3% of optimum

Subgrades for Select Fill 95%+ of ASTM D 698 -2% to +3% of optimum

General Site Fills 92%-95% of ASTM D 698 -2% to +3% of optimum

Fills behind Sheet Pile Walls 90%-92% of ASTM D 698 -2% to +3% of optimum

Select Fills 95%+ of ASTM D 698 -2% to +3% of optimum

General site fill for this project should consist of a clean clayey sands (SC), silty sands (SM), low

plasticity clays (CL), high plasticity clays (CH) or any combination of these materials with a liquid

limit of less than 50 and a plasticity index between 20 and 30. The general fill should be placed in

thin lifts, not exceeding 8-in. loose measure, and compacted as indicated above in Table 8.1.

Backfill material for placement behind sheet pile walls for this project should consist of a clean poorly

graded sands (SP), well graded sands (SW), clayey sands (SC), or silty sands (SM) or any combination

of these materials with a liquid limit of less than 30 and a plasticity index between 0 and 15. The

backfill materials should be placed in thin lifts, not exceeding 8-in. loose measure, and compacted as

indicated above in Table 8.1.

Select fill for this project should consist of a clean low-plasticity sandy clay (CL) or clayey sand (SC)

material with a liquid limit of less than 40 and a plasticity index between 7 and 20. The select fill

should be placed in thin lifts, not exceeding 8-in. loose measure, and compacted as indicated above

in Table 8.1.


Report No. 26074

8-2

Prior to any filling operations, samples of the proposed borrow materials should be obtained for soil

classification and laboratory moisture-density testing. The tests will provide a basis for evaluation of

fill compaction by in-place density testing. A qualified soil technician should perform sufficient in-

place density tests during the earthwork operations to verify that proper levels of compaction are being

attained.

8.2 Drainage

The performance of the sheet pile wall, foundation systems, and site pavement/flatwork will not only

be dependent upon the quality of construction but also upon the stability of the moisture content of

the near surface soils. Therefore, we highly recommend that site drainage be developed so that

ponding of surface runoff near structures or pavements/flatwork does not occur. Accumulations of

water near structures or pavements/flatwork could cause significant moisture variations in the soils

adjacent to the foundations and pavements/flatwork thus increasing the potential for structural

distress.


Report No. 26074

9-1

9 LIMITATIONS AND DESIGN REVIEW

9.1 Limitations

This revised report has been prepared for the exclusive use of Lockwood, Andrews and Newnam,

Inc. and the project team for specific application to the design of the proposed North Beach

Navigable Canal located in Corpus Christi, Texas. Our report has been prepared in accordance with

the generally accepted geotechnical engineering practice common to the local area. No other

warranty, express or implied, is made.

The analyses and recommendations contained in this report are based on the data obtained from

the referenced subsurface explorations within the project site. The soil boring indicates subsurface

conditions only at the specific location, time and depth penetrated. The soil borings do not

necessarily reflect strata variations that could exist at other locations within the project site. The

validity of our recommendations is based in part on assumptions about the stratigraphy made by

the Geotechnical Engineer. Such assumptions may be confirmed only during construction of the

project. Our recommendations presented in this report must be reevaluated if subsurface

conditions during the construction phase are different from those described in this report.

If any changes in the nature, design or location of the project are planned, the conclusions and

recommendations contained in this revised report should not be considered valid unless the

changes are reviewed, and the conclusions modified or verified in writing by TWE. TWE is not

responsible for any claims, damages or liability associated with interpretation or reuse of the

subsurface data or engineering analyses without the expressed written authorization of TWE.

9.2 Design Review

Review of the design and construction drawings as well as the specifications should be performed

by TWE before release. The review is aimed at determining if the geotechnical design and

construction recommendations contained in this revised report have been properly interpreted.

Design review is not within the authorized scope of work for this study.

9.3 Construction Monitoring

Construction surveillance is recommended and has been assumed in preparing our

recommendations. These field services are required to check for changes in conditions that may

result in modifications to our recommendations. The quality of the construction practices will

affect performance and should be monitored. TWE would be pleased to provide construction

monitoring, testing and inspection services for the project.

TWE Project No. 20.53.036 Report No. 26074

APPENDIX A

PROJECT INFORMATION OF LOCKWOOD, ANDREWS AND NEWNAM

NORTH BEACH NAVIGABLE CANAL CROSS SECTIONS

© 2019 Microsoft Corporation © 2019 DigitalGlobe ©CNES (2019) Distributi

DA-25

A = 5.47 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 27.38 CFS

DA-27

A = 5.87 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 29.38 CFS

DA-29

A = 6.02 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 30.13 CFS

DA-32

A = 6.02 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 30.13 CFS

DA-23

A = 5.70 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 32.92 CFS

DA-21

A = 7.01 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 40.48 CFS

DA-19

A = 9.80 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 56.60 CFS

DA-16

A = 6.43 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 37.13 CFS

DA-13

A = 6.05 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 34.94 CFS

DA-11

A = 5.79 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 33.44 CFS

DA-10

A = 2.69 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 15.53 CFS

DA-8

A = 2.76 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 15.94 CFS

DA-7

A = 6.51 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 37.60 CFS

DA-5

A = 5.27ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 30.43 CFS

DA-4

A = 4.01 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 23.16 CFS

DA-1

A = 8.16 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 47.12 CFS

DA-3

A = 4.91 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 24.57 CFS

DA-6

A = 7.56 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 37.84 CFS

DA-24

A = 2.38 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 11.91 CFS

DA-26

A = 2.22 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 11.11 CFS

DA-28

A = 2.40 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 12.01 CFS

DA-30

A = 2.50 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 12.51 CFS

DA-31

A = 1.24 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 6.21 CFS

DA-22

A = 2.53 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 12.66 CFS

DA-20

A = 2.68 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 13.41 CFS

DA-18

A = 2.83 ACRES

Tc=30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 14.16 CFS

DA-17

A = 3.36 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 16.82 CFS

DA-15

A = 3.33 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 16.67 CFS

DA-14

A = 3.29 ACRES

Tc=30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 16.47 CFS

DA-12

A = 3.71 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 18.57 CFS

DA-9

A = 8.83 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.75

Q100 = 50.99 CFS

DA-2

A = 2.05 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 10.26 CFS

DA-33

A = 3.00 ACRES

Tc = 30 min.

I100 = 7.70 IN./HR.

C = 0.65

Q100 = 15.02 CFS

SOUTH

OUTFALL

Q TOTAL = 30.2 CFS

CANAL OUTFALL

Q TOTAL = 826.3 CFS

NORTH OUTFALL

Q TOTAL = 99.9 CFS

EXHIBIT NO,1


APPENDIX B

SOIL BORING LOCATION PLAN

TWE DRAWING NO. 20.53.036-1 AND 20.53.036-2

COPYRIGHT © 2015 GOOGLE EARTH. ALL RIGHTS RESERVED.

COPYRIGHT © 2015 GOOGLE MAP. ALL RIGHTS RESERVED.

20

B-1

PROJECT

LOCATION

Navigable Canal

COPYRIGHT © 2015 GOOGLE EARTH. ALL RIGHTS RESERVED.

COPYRIGHT © 2015 GOOGLE MAP. ALL RIGHTS RESERVED.

20

B-2

PROJECT

LOCATION

Navigable Canal


APPENDIX C

LOGS OF PROJECT BORINGS AND A KEY TO

TERMS AND SYMBOLS USED ON BORING LOGS

0

5

10

15

20

25

30

35

Stiff dark gray SANDY SILTY CLAY (CL-ML) with shells

Loose tan and gray SILTY SAND (SM) with shells

-color changes to tan with abundant shells

Medium dense tan POORLY GRADED SAND with SILT(SP- SM) with abundant shells

Medium dense gray POORLY GRADED SAND withSILT (SP-SM)

-becomes loose

Very soft tan and gray LEAN CLAY with SAND (CL)

-color changes to gray

-becomes firm (P) 0.75

7/6"8/6"5/6"

1/6"1/6"5/6"

2/6"4/6"5/6"

3/6"9/6"10/6"

2/6"5/6"6/6"

4/6"7/6"9/6"

3/6"2/6"3/6"

W.O.H

W.O.H

18

19

22

24

43

30 90

23

NP

45

2

NP

30

0.65 7.8 (15)

29

7

9

5

73

72 (1)

TOLUNAY-WONG ENGINEERS, INC.

LOG OF BORING B-1PROJECT: North Beach Navigable Canal

Coprus Christi, TexasCLIENT: Lockwood, Andrews & Newnam, Inc.

Corpus Christi, Texas

COMPLETION DEPTH: 50 ft REMARKS: Free water was encountered at a depth of 4.5-ft. below existing grade during dryauger drilling. After a 15 minute waiting period, water was at a depth of 3.8-ft. Atcompletion of drilling and sampling, the open bore hole was back filled with soilcuttings and bentonite pellets.

DATE BORING STARTED: 7-6-20DATE BORING COMPLETED: 7-6-20LOGGER: J.GonzalesPROJECT NO.: 20.53.036

Page of1

DE

PT

H (

ft)

SA

MP

LE

TY

PE

SY

MB

OL/U

SC

S

MATERIAL DESCRIPTION

COORDINATES: N 27° 49' 01.6"W 97° 23' 30.9"

SURFACE ELEVATION:DRILLING METHOD:

Dry Augered: 0.0-ft. to 6.0-ft.Wash Bored: 6.0-ft. to 50.0-ft.

(P)

PO

CK

ET

PE

N (

tsf)

(T)

TO

RV

AN

E (

tsf)

ST

D.

PE

NE

TR

AT

ION

TE

ST

(b

low

s/f

t)

MO

IST

UR

EC

ON

TE

NT

(%

)

DR

Y U

NIT

WE

IGH

T(p

cf)

LIQ

UID

LIM

IT(%

)

PL

AS

TIC

ITY

IND

EX

(%

)

CO

MP

RE

SS

IVE

ST

RE

NG

TH

(ts

f)

FA

ILU

RE

ST

RA

IN (

%)

CO

NF

ININ

GP

RE

SS

UR

E (

psi

)

PA

SS

ING

#20

0S

IEV

E (

%)

OT

HE

R T

ES

TS

PE

RF

OR

ME

D

2

35

40

45

50

55

60

65

70

Soft gray FAT CLAY (CH) with iron oxide stains

Loose tan and gray CLAYEY SAND (SC) with sandseams

-becomes very loose

Bottom @ 50'

(P) 0.5

3/6"3/6"5/6"

1/6"2/6"1/6"

14

25

62 93 68 97

16

(2)





COMPLETION DEPTH: 50 ft REMARKS: Free water was encountered at a depth of 4.5-ft. below existing grade during dryauger drilling. After a 15 minute waiting period, water was at a depth of 3.8-ft. Atcompletion of drilling and sampling, the open bore hole was back filled with soilcuttings and bentonite pellets.


Page of2

DE

PT

H (

ft)

SA

MP

LE

TY

PE

SY

MB

OL/U

SC

S


COORDINATES: N 27° 49' 01.6"W 97° 23' 30.9"



(P)

PO

CK

ET

PE

N (

tsf)

(T)

TO

RV

AN

E (

tsf)

ST

D.

PE

NE

TR

AT

ION

TE

ST

(b

low

s/f

t)

MO

IST

UR

EC

ON

TE

NT

(%

)

DR

Y U

NIT

WE

IGH

T(p

cf)

LIQ

UID

LIM

IT(%

)

PL

AS

TIC

ITY

IND

EX

(%

)

CO

MP

RE

SS

IVE

ST

RE

NG

TH

(ts

f)

FA

ILU

RE

ST

RA

IN (

%)

CO

NF

ININ

GP

RE

SS

UR

E (

psi

)

PA

SS

ING

#20

0S

IEV

E (

%)

OT

HE

R T

ES

TS

PE

RF

OR

ME

D

2

0

5

10

15

20

25

30

35

Very stiff dark gray SANDY SILTY CLAY (CL-ML) withshells

Very loose tan POORLY GRADED SAND with SILT(SP-SM) with shells

-becomes loose

-with abundant shells

Loose gray POORLY GRADED SAND (SP)

Very loose gray CLAYEY SAND (SC) with sand seams

-becomes loose

-becomes very loose

Very soft gray LEAN CLAY (CL) with silt seams andshell fragments

10/6"13/6"10/6"

2/6"1/6"1/6"

1/6"3/6"2/6"

3/6"3/6"2/6"

2/6"3/6"3/6"

1/6"W.O.H

3/6"4/6"6/6"

W.O.H

W.O.H

W.O.H

6

19

26

36

34

22

NP

NP

30

1

NP

NP

11

60

10

3

15

38





COMPLETION DEPTH: 50 ft REMARKS: Free water was encountred at a depth of 4.0-ft. below existing grade during dryauger drilling. After a 15 minute waiting period, water was at a depth of 4.8-ft. Atcompletion of drilling and sampling, the open bore hole was back filled with soilcuttings and bentonite pellets.


Page of1

DE

PT

H (

ft)

SA

MP

LE

TY

PE

SY

MB

OL/U

SC

S


COORDINATES: N 27° 49' 46.8"W 97° 23' 02.7"



(P)

PO

CK

ET

PE

N (

tsf)

(T)

TO

RV

AN

E (

tsf)

ST

D.

PE

NE

TR

AT

ION

TE

ST

(b

low

s/f

t)

MO

IST

UR

EC

ON

TE

NT

(%

)

DR

Y U

NIT

WE

IGH

T(p

cf)

LIQ

UID

LIM

IT(%

)

PL

AS

TIC

ITY

IND

EX

(%

)

CO

MP

RE

SS

IVE

ST

RE

NG

TH

(ts

f)

FA

ILU

RE

ST

RA

IN (

%)

CO

NF

ININ

GP

RE

SS

UR

E (

psi

)

PA

SS

ING

#20

0S

IEV

E (

%)

OT

HE

R T

ES

TS

PE

RF

OR

ME

D

2

35

40

45

50

55

60

65

70

Very soft FAT CLAY (CH) with sand seams

-becomes firm with silt seams

Bottom @ 50'

(P) 0.25

(P) 0.5

(P) 0.5

87

64

51

98

69

39

103

21

74

0.94 2.9 (21)

87

99

93

(2)

(1)





COMPLETION DEPTH: 50 ft REMARKS: Free water was encountred at a depth of 4.0-ft. below existing grade during dryauger drilling. After a 15 minute waiting period, water was at a depth of 4.8-ft. Atcompletion of drilling and sampling, the open bore hole was back filled with soilcuttings and bentonite pellets.


Page of2

DE

PT

H (

ft)

SA

MP

LE

TY

PE

SY

MB

OL/U

SC

S


COORDINATES: N 27° 49' 46.8"W 97° 23' 02.7"



(P)

PO

CK

ET

PE

N (

tsf)

(T)

TO

RV

AN

E (

tsf)

ST

D.

PE

NE

TR

AT

ION

TE

ST

(b

low

s/f

t)

MO

IST

UR

EC

ON

TE

NT

(%

)

DR

Y U

NIT

WE

IGH

T(p

cf)

LIQ

UID

LIM

IT(%

)

PL

AS

TIC

ITY

IND

EX

(%

)

CO

MP

RE

SS

IVE

ST

RE

NG

TH

(ts

f)

FA

ILU

RE

ST

RA

IN (

%)

CO

NF

ININ

GP

RE

SS

UR

E (

psi

)

PA

SS

ING

#20

0S

IEV

E (

%)

OT

HE

R T

ES

TS

PE

RF

OR

ME

D

2


APPENDIX D

SHEET PILE WALL GLOBAL STABILITY RESULTS

2.2852.285

W

W

250.00 lbs/ft22.2852.285

Phi (deg)

Cohesion (psf)

Strength Type

Unit Weight (lbs/ft3)

ColorMaterial Name

240Mohr-

Coulomb120Stiff Fat Clay

270Mohr-

Coulomb110Loose Sand

270Mohr-

Coulomb115

Med-Dense Sand

180Mohr-

Coulomb105

Very Soft Lean Clay

270Mohr-

Coulomb117Firm Lean Clay

180Mohr-

Coulomb110Soft Lean Clay

270Mohr-

Coulomb105

Very Loose Sand

40

20

0-2

0

-60 -40 -20 0 20 40 60

ScenarioMaster Scenario

GroupGroup 1

CompanyTolunay-Wong Engineers, Inc.

Drawn ByJ. Buchen

File NameDate8/14/2020

Project

SLIDEINTERPRET 9.007B-1 Long-Term Anchored

North Beach Navigable Canal

2.6412.641

W

W

250.00 lbs/ft2

2.6412.641

Phi (deg)Cohesion (psf)Strength TypeUnit Weight (lbs/ft3)ColorMaterial Name

240Mohr-Coulomb120Stiff Fat Clay

270Mohr-Coulomb110Loose Sand

270Mohr-Coulomb115Med-Dense Sand

180Mohr-Coulomb105Very Soft Lean Clay

270Mohr-Coulomb117Firm Lean Clay

180Mohr-Coulomb110Soft Lean Clay

270Mohr-Coulomb105Very Loose Sand

40

20

0-2

0-4

0

-60 -40 -20 0 20 40 60


GroupGroup 1


Drawn ByJ. Buchen


Project

SLIDEINTERPRET 9.007B-1 Long-Term Cantilever


1.6371.637

W

W

250.00 lbs/ft2

1.6371.637









40

20

0-2

0-4

0

-60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60


GroupGroup 1


Drawn ByJ. Buchen


Project

SLIDEINTERPRET 9.007B-1 Short-Term Anchored


1.7151.715

W

W

250.00 lbs/ft2

1.7151.715









20

0-2

0-4

0

-60 -40 -20 0 20 40 60


GroupGroup 1


Drawn ByJ. Buchen


Project

SLIDEINTERPRET 9.007B-1 Short-Term Cantilever


2.4082.408

W

W

250.00 lbs/ft2

2.4082.408

Phi (deg)

Cohesion (psf)

Strength TypeUnit Weight (lbs/

ft3)ColorMaterial Name

27100Mohr-

Coulomb120Very Stiff Sandy Clay

270Mohr-

Coulomb105Very Loose Sand

270Mohr-


260Mohr-

Coulomb105

Very Soft Lean Clay Upper

31100Mohr-

Coulomb105

Very Soft Lean Clay Lower

31100Mohr-


20

10

0-1

0-2

0-3

0-4

0

-50 -40 -30 -20 -10 0 10 20 30 40 50


GroupGroup 1


Drawn ByJ. Buchen


Project

SLIDEINTERPRET 9.007B-2 Long-Term Anchored


3.1663.166

W

W

250.00 lbs/ft2

3.1663.166

Phi (deg)

Cohesion (psf)

Strength Type


ColorMaterial Name

27100Mohr-


270Mohr-


270Mohr-


260Mohr-

Coulomb105


31100Mohr-

Coulomb105


31100Mohr-


20

0-2

0-4

0

-60 -40 -20 0 20 40 60


GroupGroup 1


Drawn ByJ. Buchen


Project

SLIDEINTERPRET 9.007B-2 Long-Term Cantilever


2.0762.076

W

W

250.00 lbs/ft2

2.0762.076

Phi (deg)

Cohesion (psf)

Strength Type


ColorMaterial Name

02800Mohr-


270Mohr-


270Mohr-


0250Mohr-

Coulomb105


0940Mohr-

Coulomb105


0940Mohr-


0940Mohr-


20

0-2

0-4

0

-60 -40 -20 0 20 40 60


GroupGroup 1


Drawn ByJ. Buchen


Project

SLIDEINTERPRET 9.007B-2 Short-Term 2 Anchored


2.0762.076

W

W

250.00 lbs/ft2

2.0762.076

Phi (deg)Cohesion

(psf)Strength Type


ColorMaterial Name

02800Mohr-


270Mohr-


270Mohr-


0250Mohr-

Coulomb105


0940Mohr-

Coulomb105


0940Mohr-


0940Mohr-


20

0-2

0-4

0

-60 -40 -20 0 20 40 60


GroupGroup 1


Drawn ByJ. Buchen


Project

SLIDEINTERPRET 9.007B-2 Short-Term 2 Cantilever



APPENDIX E

CONSOLIDATED-UNDRAINED TRIAXIAL SHEAR TEST RESULTS

geotechnical investigation report (tolunay-wong engineering, inc.) · 2021. 1. 22. · of soils...

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